I just spent an hour or so watching videos on the Revoice Pro website. It seems like a very cool, powerful program. I don't, however, see anything it can do that can't be done with Melodyne Studio and SONAR.
So Studio One is now going to have a feature SONAR has had for some time. Good for them. Using a derogatory term for Vocalsync reminds me of a MOPAR guy that thinks everything that Ford or Chevy make is junk.
Vocalign and Vocalsync do the same thing. Personally I think it's better to perform the parts correctly in the first place.